Michael Richardson, For The Straits Times 23 Nov 09;
NEARLY everyone is familiar with budgets. Households keep them. So do companies and national governments. But what about the carbon budget that measures the health of the earth's climate system?
Just as accountants check financial budgets, an international team of scientists is attempting to do the same for the planet's carbon budget. Carbon is the core of organic molecules from which all forms of life are built.
The carbon cycle is a complex series of processes in which all the carbon atoms on earth rotate through the land, sea and atmosphere, and are kept in a shifting balance. The ocean and land are natural sponges, or sinks, that absorb carbon in its gaseous form - carbon dioxide (CO2).
Ocean-dwelling plankton and land plants, including forests and grasslands, take in CO2 by photosynthesis. But there is a reverse process. Seawater also releases CO2 into the atmosphere, as do land plants and soil.
The natural carbon cycle has been influenced by the growing human population and its demands for resources, especially for fossil fuel and land. Carbon dioxide accounts for nearly 77 per cent of the global greenhouse gas emissions blamed by many scientists for warming the earth to potentially dangerous levels.
According to the 2007 report of the Intergovernmental Panel on Climate Change, nearly all of this CO2 came from two sources: burning coal, oil and natural gas; and clearing forests for farming and other uses.
Compiling a global carbon budget is not easy. But a group of 31 oceanographers and other specialists attached to academic institutions and government- funded climate agencies in the United States, Europe, Asia, Australia and South America published last week their latest annual stock-take.
They found that despite the economic slowdown that started to bite in the second half of last year, the concentration of CO2 in the atmosphere rose by 1.8 parts per million last year, slightly below the annual average of 1.9 ppm between 2000 and last year. This might not sound like much. But 1 ppm of CO2 corresponds to more than 2 billion tons of carbon and nearly 8 billion tons of CO2.
The increase brought atmospheric CO2 concentration to 385 ppm last year, 38 per cent above 280 ppm at the start of the industrial revolution in 1750 and the highest point for at least 2 million years.
The lead author of the Global Carbon Project study, Professor Corinne Le Quere of the University of East Anglia and the British Antarctic Survey, says that the only way to control climate change and keep the temperature rise to a tolerable level is through a drastic reduction in global CO2 emissions.
Yet, the prospects for effective action when over 190 nations gather next month for the United Nations climate conference in Copenhagen seem dim, with negotiations set to drag on into next year and perhaps beyond.
On one level, an agreement should be feasible. Just three countries - China, the US and India - were responsible for half of global CO2 fossil fuel emissions last year. These three, plus Russia, Japan and the European Union, accounted for 80 per cent of all emissions.
The leading polluters have been meeting as a group to try to decide how to apportion and pay for the cuts, but they remain deeply divided. Finding an equitable and politically acceptable solution is a test of statesmanship that appears to be beyond most of the key participants.
The biggest rise in fossil fuel emissions in the last decade has taken place in developing countries, while developed countries on average show steady emissions. But from a historical perspective, developing countries account for only about 20 per cent of cumulative fossil fuel emissions since 1750.
Moreover, about one quarter of the recent growth in developing country emissions resulted from the increase in international trade of goods and services produced there but consumed in developed countries. If these are added to the 45 per cent emissions tally of developed countries last year, the advanced economies are still the main source of worldwide CO2 emissions.
This kind of accounting is a recipe for international contention. Meanwhile, the global carbon balance may be on the verge of a serious deficit as the amount of CO2 from human activity being spewed into the atmosphere outstrips the capacity of natural sinks to absorb it. Global emissions from the burning of fossil fuel and deforestation now amount to 37 billion tons of CO2 per year, 41 per cent higher than in 1990.
Land and sea sinks removed an average of 57 per cent of all CO2 from human activities between 1958 and last year, leaving 43 per cent in the atmosphere, where it will stay for at least several centuries.
The research of Prof Le Quere and her colleagues indicates that the portion of CO2 remaining in the atmosphere may be rising. US oceanographer Richard Feely, who is part of the Global Carbon Project, says: 'We're concerned that if the natural sinks can't keep pace with the increased CO2 emissions, then the physical and biological impacts of global warming will accelerate over the next century.'
There is disagreement among scientists about whether the capacity of earth's biosphere to keep the global carbon budget in balance has already been exceeded. But even those who dispute that the tipping point has arrived say that it will certainly come unless resolute steps are taken to curb global greenhouse gas emissions.
The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies.
